The bar was so dark I could hardly see Lindsay Lohan’s face, but her bee-stung lips were the centre of attention, and her eyes expressive despite the shadows. It was her idea to meet there – not just the Connaught Hotel, but the bar, though another room had been arranged – and when I was summoned she was already sitting with two men in a booth. She got up to greet me with a distracted, tobacco-scented air kiss and a faint waft of something sharper.

She was tall, in towering black leather wedge boots – Givenchy, she told me as she adjusted one of the gold buckles, and these were the second pair she’d bought. There was a patch of pale leg above them, a long, dark polka-dotted chiffon shirt over a slip, and a well-tended tumble of strawberry blonde hair. When she sat, she slouched, so that she was all hair and heels, her shaded face conspiratorially close. Among the many bracelets on her wrists was a bangle given to her by Elizabeth Taylor’s nurse – Lohan played Taylor two years ago in a TV movie– and her fingers were decorated with tiny written tattoos, one of which read: “Shhhhhh!”

If that was intended as a note to self, Lohan showed no signs of heeding it. She had talked all day, she said, in rehearsals for her first ever play – David Mamet’s Speed-the-Plow – and even though her voice was husky and cracked, she went on for another hour: fast, as if speech were a form of transport, and she needed to get somewhere in a hurry.

“You know, when you think about it, I was doing other things before this, and I was travelling, and I come back and I’m looking at this thing and I’m like: 'Oh f---.’ The whole of Act Two, I just speak throughout the whole thing. And it’s very precise, and he has meaning behind each word, and I’m figuring that out now, and today was the first kind of day that I – we’ve only been rehearsing for a week and a half – today is my first day that I kind of started to understand it?”

“It feels really cool. It feels really good. It does. It’s… terrifying, at times. Because in the beginning I, like, panicked. I was like: Oh my f---, I can’t say all this s---.”

When Lohan swore, which she really only did at the beginning of the interview, she said the words staccato, with barely a vowel, like a sneeze. She was hilariously honest about the process and the pressures. When I asked if she was worried about memorising the lines, she gave me an “are-you-crazy?” look, and guffawed for emphasis. “YE-ah!” she said.

In Speed-the-Plow, a dissection of soul-selling in the movie industry, Lohan plays Karen, a temporary secretary taken on by a Hollywood producer. She doesn’t appear until some way into the play, but before she does we are given to understand that she is unable to work the phone or make the coffee – also, that she’s “cute”. She will go on to seduce the producer, and to champion a strange book, driven by ambiguous motives. “I’ve been depraved, too, I’ve been frightened,” she tells her boss. “I know what it is to be bad… I know what it is to be lost.”

Lindsay Posner, who is directing this West End production and has done more Mamet plays than anyone else in the UK, says he wanted Lohan for the part because “she has a mixture of vulnerability and confidence and ambition. Part of the ambiguity of the role is that the audience isn’t quite sure whether she’s a naive girl who’s out of her depth, or a calculating opportunist. That’s part of what makes the play interesting. She also needs to be sexually charismatic.”

When the play premiered on Broadway in 1988, Karen was played by Madonna. Since then, other non-professional stage actors have taken it on, partly because much of the heavy lifting in the script can be done with the crutch of a book to hand, from which lines are supposed to be read out. Even so, Lohan’s chaotic reputation precedes her, and she hasn’t made things easy for herself. When you’re known for being unreliable – for not turning up on set and not turning up at community service even when that breaks the terms of your probation for drink driving – a 10-week run in the West End, never having been on stage before and after only four weeks of rehearsal, seems a lot to ask. The word is that she is “uninsurable”, and the poster even plays on that. It’s a strip of celluloid that shows a close-up of Lohan’s face, orange at the edges, as if about to catch fire.

Lohan knows what she’s up against. “I’m there. I’m there early. I’m there early. And the next day I’m up at 7am. And I’m 10 minutes late – 10 minutes late – and I’m like apologising. I was crying yesterday. I was like, 'I’m so sorry, I’m so sorry, I’m 10 minutes late.’ I felt bad, I felt bad. I’m sounding like my character now, I keep repeating myself, oh my god.”

They are halfway through their rehearsal period, and Posner says that although he’s had to fight off some naysayers, “one just has to ignore all that, and shrug it off”. He’s been surprised by how quickly Lohan has taken to it – more so than other Hollywood actors he’s worked with, such as Julia Stiles or Aaron Eckhart or Juliette Lewis.

It’s easy to say this could be a turning point for her – almost anything can be seen as a turning point. But genuinely, this play could make all the difference.

Last year, after her sixth stint in rehab, Lohan decided to star in a reality TV series made by Oprah Winfrey. The premise: Winfrey would keep her on the straight and narrow, and Lohan would make a comeback. The result: Winfrey harangued and patronised Lohan, quizzed her parents, planted people who were supposed to help her but who then gave up on her ostentatiously. In short, Lohan fell off the wagon and was exposed.

She had moved to New York to get away from LA, and now she has moved to London to get away from New York. “After the Oprah show it was kind of hard for me to be in New York,” she said at the Connaught bar. “There started to be paparazzi, and I didn’t have that in New York in the beginning. People have had this misconception of me, that I love that attention. And that’s what they’ve made me out to be. But I never wanted that. I accepted it – I didn’t have a choice. Every time I left my house they were at the corner. Every time I went down a side street they were at the corner. If I tried to lose them they’d chase me and I’d get in an accident. That’s what happens.”

There are some grey areas in all of this. As Lohan admits, when she was young, and saw Britney Spears in magazines, she thought she wanted to be like that. “And then once I started to have it, I was like: Oh, f---. I can’t do anything.” Yet no one in Lohan’s family has not had a reality show. Before Lindsay, there was Living Lohan, in which her mother and three younger siblings attempted to show that they were just another suburban family from Long Island. There were also her dad’s 10 episodes of Celebrity Rehab with Dr Drew.

Michael Lohan, who used to work with Wolf of Wall Street protagonist Jordan Belfort, has repeatedly sold his daughter downstream – publishing tapes of her sobbing, or issuing appeals to her live on TV. Dina Lohan divorced him when he punched her brother so hard he ended up in a coma. The case of Dina is more complicated, since she and Lohan are close, but there has certainly been some vicarious living, and a large commission taken from Lohan’s earnings. Tales of the Lohans’ egregious parenting are legion. As one American talk show host put it: “If her parents were any more low-rent, they’d be a spring break destination.”

They are partly responsible for the striking extent to which Lohan’s life has been filmed. Never has the phrase “caught on camera” been so literal or so routine.A film by Garry Sykes called LXHXN, and brilliantly subtitled “A War Movie”, is made entirely of footage of Lohan found on YouTube. There are home movies, movies, live appearances, talk show interviews, infrared surveillance, news stories and court tapes. And there’s only one conclusion to be drawn from watching it: however much she has colluded, Lohan’s life has been a persecution.

'You thought she was going to be one of those scary Hollywood stories?” Oprah Winfrey said on camera to Dina Lohan, nodding gravely, as if they weren’t both a part of it. Well, yes. Lohan is already a textbook Hollywood story, and she’s only 28. But she doesn’t have to be a scary one.

She started acting – at least, started modelling and doing commercials – when she was three years old. She was, it was said, the first redhead the Ford agency had ever taken on. When she was 11 she pretended to be ill so she could skip school and go to her first movie audition. She got the part – or parts, since she had to play twins who are separated as babies and end up at the same summer camp, one of them with a posh English accent. Lohan still remembers how long the shoot for The Parent Trap was: “eight months, three weeks and two days”. It changed her life, and to some extent, it changed the fortunes of Disney Studios, who realised they had found in Lohan their latest live-action princess.

Lindsay Lohan played twins in the 1998 remake of The Parent Trap (Everett Collection/Rex Features)

She went on to do more for them – including the preposterous Life-Size, in which a Barbie doll Lohan is given comes to life and turns into Tyra Banks – and excelled herself with the remake of Freaky Friday, in which she is trapped inside the body of her mother, played by Jamie Lee Curtis. A year later she starred in Mean Girls, still a cult classic of teen behaviour. “I had gone from home-schooled jungle freak to shiny Plastic to most hated person in the world to actual human being,” she says at the end of that film, mirroring a certain trajectory of her own.

Together, these films made Lohan a star of proportions that would put any 17-year-old at risk. She was commanding $7 million per picture. She was handed bonuses of $1 million just like that. And part of the reason it was dangerous was that Lohan wasn’t just a star: she was an actress. In every one of those performances – tween fodder though the films were – she showed vulnerability, honesty and smart comic timing. She was more raw than the Olsen twins or Hilary Duff. That’s why it worked. Someone, surely, should have seen that the qualities that led her to succeed on screen might one day render her fragile off it? If Hollywood made her, why didn’t Hollywood protect her?

She grew up a little – she was excellent as Meryl Streep’s daughter in Robert Altman’s last film, A Prairie Home Companion – and then, in 2007, when she was making the mediocre movies Georgia Rule and I Know Who Killed Me, she started to come apart at the seams.

“I called my mom,” she told me. “I was like, I just want to come home. I want to come home. I don’t want to do this. I want to be with you guys. I miss you guys, I just want to come home. And that’s when all the court s--- started to hit.” That year she was arrested twice for drink driving. She was sentenced to 36 months probation, and had three stays in rehab.

“I was kind of hanging on to nothing. I was by myself for a long time. And it was hard to be in LA – I had this beautiful house, and these things, which really don’t, essentially, mean anything. And it was… it was rough for a minute. But then I thought: I can just put my ducks in order and figure it out.”

Lohan was saying all this outside the Connaught bar. She had wanted to smoke a cigarette, and asked me to come with her so we could keep talking. It was warm, and there was an orange tone to the evening light that made her face and hair glow to match it. She was talking about the shape that’s been given to her life in the press, and whether she recognised herself in it. “Living a life in the public eye – that, I could have taken more responsibility for,” she said. “But I didn’t know how. Honestly, I didn’t know how. I didn’t realise it – I’ve never Googled myself, I don’t understand it.”

When she became famous for being famous, then famous for being drunk, she was easy prey. In 2008, she posed naked as Marilyn Monroe for the cover of New York magazine, allowing the photographer Bert Stern to replicate his famous “last sitting” shots of Monroe. Who decided that wasn’t tempting fate?

Then last year she took on the role of a ravaged being in an excruciating production called The Canyons. Behind the scenes, the film didn’t exactly sound like a recipe for salvation: directed by the burnt-out screenwriter of Taxi Driver (Paul Schrader) and written by the burnt-out author of American Psycho (Bret Easton Ellis), it co-starred the porn actor James Deen and contractually obliged her to perform group sex. In a widely read New York Times article, the shoot was portrayed as profoundly sadistic. Yet on screen, Lohan is gripping: sarcastic, dark, already half-destroyed. Made up like an old-school Liz Taylor, she appears naked and bruised, sobbing while still believing herself to be in control.

In her private life things weren’t much better. The California courts had decided that her sentence for drink driving and violation of probation should include not only jail time but 12-hour shifts in a morgue. For four months, she worked from 4am to 4pm. It was, as she puts it, “F’d up and inappropriate – because a lot of other people were meant to do it, and they were like: 'No, they can’t handle it. Lohan can.’ It’s different for me than it would be for other people – like, no one would really have to work at the morgue in LA and roll a body bag for Whitney Houston.”

Still, she made the best of it: “I know it sounds really dark and strange, but I thought it would be a lot worse. I kind of regulated a lot of it. I’d tell people: 'You didn’t fold that sheet properly’, because I’m OCD with folding.” It took her a while, she said, to see the point of the “road blocks” that were being put in her path. And then she had an epiphany. “I was like: OK, wait. Something needs to change, and I think that’s me.”

Later, when I listened to the recording of the interview, I realised that much of Lohan’s speech was patterned around the art of recovery: “Yes, I’ve made mistakes. But who doesn’t in life?”; “I like to learn the hard way. But I’ve learnt enough the hard way, and I don’t ever want to have to learn that way again”; “There’s really nothing left in that life for me”. These had the mantra-like tone of phrases often repeated, and in themselves were not unusual. But the effect at the time was one of great urgency and soul-baring. She swung into the role of interviewee as if it were a one-act, one-woman play, and it was hard not to feel you were witnessing a life conducted at a high frequency, with high stakes.

The confessional aspect is, of course, part of who she is now: Lohan spills over. When two strangers interrupted us to say hello to her, she invited them to sit down and gave them advice about their children. When a man on the street recognised her and said Speed-the-Plow was a fantastic play, she said a heartfelt “thank you” from deep in her throat, as if giving a low bow from a stage. When she told me that she and Lindsay Posner had become “really close”, it took a moment for me to remember they’d worked together for less than two weeks.

I asked her where she saw herself in 20 years’ time, and she laughed. “I can go with five,” she said. “That’s as far as I can go.” Then she went on: “I’m glad that I’m finding my way. I want to work for this next year, and then take some time, and hopefully fall in love, and hopefully have a family. Now I see all these kids that are living so fast. I think: I’ve been there. I want to hold them, and say: it’s not worth it.”

I asked if there was anyone in particular she was thinking of starting a family with, and she smirked so uncontrollably it looked for a moment as though her face might cave in. “That’s not my focus right now, though, anyway,” she said, regaining her composure. She’d like to be nominated for an Oscar, she added, and has a role lined up: Clara Bow, a Hollywood redhead who started young and died mad – due, some said, to the fact that her mother had once tried to kill her.

But Lohan’s golden opportunity just now is the Mamet play. “I like the idea of being able to fight for what I lost, essentially,” she explained. “I lost a lot of… I wouldn’t say… I don’t think 'respect’ is the word… trust from a lot of people. And I don’t mind gaining that back.”

Posner has high hopes. “I have every confidence that the media, the profession and indeed the American film industry will be reminded once again of how good she is as an actress,” he suggests. “I do think that will happen, and I think it will be wonderful if it does.”

I was surprised by how much I wanted these things to come true for Lohan. Because look how we prey on these people; how we pry. Why do we never behave as we do at tennis matches, cheering on our stars when they need a surge of support?Heath Ledger, Philip Seymour Hoffman: how far back would we have had to go in those modern Hollywood lives to find a point where, instead of staring, we could have said: we’re rooting for you? In Lohan’s case, this may be it. I felt I was watching her teeter on the brink of something, and it seemed important that she should fall forward this time, into the life she wanted.